# US 12,591,026 B2 · Tunnel magnetoresistance element to detect out-of-plane changes in a magnetic field intensity of a magnetic field

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- Number: US 12,591,026 B2
- Document ID: US12591026B2
- Status: Granted
- Kind: B2
- Application number: 18/333,765
- Filed: 2023-06-13
- Published: 2024-12-19
- Granted: 2026-03-31
- Earliest claimed: 2023-06-13
- Assignees: Allegro MicroSystems, LLC; Commissariat A L'energie Atomique Et Aux Energies Alternatives
- Applicants: Allegro MicroSystems, LLC; Commissariat à l'énergie atomique et aux énergies alternatives
- Inventors: Paolo Campiglio; Doan Nguyen Ba; Maxime Rioult; Aurélie Solignac; Jean-Michel Daga
- Web page: https://patentgrep.com/patent/US12591026B2

## CPC

- G01R 33/093: {using multilayer structures, e.g. giant magnetoresistance sensors (thin magnetic films H01F10/00)}
- G01R 33/0052: {Manufacturing aspects; Manufacturing of single devices, i.e. of semiconductor magnetic sensor chips (devices based on galvano-magnetic effect or the like H10N50/85)}
- G01R 33/098: {comprising tunnel junctions, e.g. tunnel magnetoresistance sensors}
- H01F 10/3272: {by use of anti-parallel coupled [APC] ferromagnetic layers, e.g. artificial ferrimagnets [AFI], artificial [AAF] or synthetic [SAF] anti-ferromagnets}
- H01F 10/3286: {Spin-exchange coupled multilayers having at least one layer with perpendicular magnetic anisotropy}
- H10N 50/01: Manufacture or treatment
- H10N 50/10: Magnetoresistive devices
- H10N 50/85: Materials of the active region
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR

## Abstract

In one aspect, a method includes manufacturing a tunneling magnetoresistance (TMR) element to sense out-of-plane changes in magnetic field intensity in a magnetic field. The manufacturing includes depositing a plurality of antiferromagnetic layers having magnetization directions alternating by layer between a first direction and a second direction opposite the first direction. A top layer of the plurality of antiferromagnetic layers has a magnetization direction in the first direction. The manufacturing also includes depositing a ferromagnetic layer directly on the top layer; depositing a first multilayer structure directly on the ferromagnetic layer; depositing a metal layer directly on the first multilayer structure; and depositing a second multilayer structure directly on the metal layer. The ferromagnetic layer, the first multilayer structure, and the second multilayer structure are each parallel to an x-y plane and the first direction is either in a z-direction or in a −z direction.

## Claims

### Claim 1

A method comprising:
manufacturing a tunnel magnetoresistance (TMR) element to sense out-of-plane changes in magnetic field intensity in a magnetic field, the manufacturing comprising:
depositing antiferromagnetic material on a seed layer, the antiferromagnetic material comprising a plurality of antiferromagnetic layers having magnetization directions alternating by layer between a first direction and a second direction opposite the first direction, a top layer of the plurality of antiferromagnetic layers having a magnetization direction in the first direction;
depositing a ferromagnetic layer directly on the top layer of the plurality of antiferromagnetic layers;
depositing a first multilayer structure directly on the ferromagnetic layer;
depositing a metal layer directly on the first multilayer structure; and
depositing a second multilayer structure directly on the metal layer,
wherein the ferromagnetic layer, the first multilayer structure, and the second multilayer structure are each parallel to an x-y plane,
wherein the first direction is either in a z-direction or in a −z direction,
wherein a magnetization direction of the second multilayer structure is in the second direction and is determined by and is opposite of the magnetization direction of the top layer of the plurality of antiferromagnetic layer, and
wherein the magnetization direction of the second multilayer structure is a reference direction of the TMR element.

### Claim 2 (depends on 1)

The method of claim 1, wherein the ferromagnetic layer is a first magnetic layer, and further comprising:
depositing a second ferromagnetic layer on the second multilayer structure;
depositing an insulator layer directly on the second ferromagnetic layer; and
depositing a free layer on the insulator layer.

### Claim 3 (depends on 2)

The method of claim 2, wherein a magnetization direction of the free layer lies within the x-y plane.

### Claim 4 (depends on 2)

The method of claim 2, further comprising depositing a striped domain structure on the free layer.

### Claim 5 (depends on 4)

The method of claim 4, wherein depositing the striped domain structure on the free layer comprises depositing the striped domain structure comprising one or more sublayers.

### Claim 6 (depends on 5)

The method of claim 5, wherein each sublayer comprises at least one heavy metal and at least one ferromagnetic material.

### Claim 7 (depends on 5)

The method of claim 5, wherein each sublayer comprises at least one oxide layer and at least one ferromagnetic layer.

### Claim 8 (depends on 7)

The method of claim 7, wherein each sublayer further comprises at least one heavy metal.

### Claim 9 (depends on 5)

The method of claim 5, wherein each sublayer further comprises a buffer layer.

### Claim 10 (depends on 2)

The method of claim 2, wherein the metal layer is a first metal layer, and further comprising depositing a second metal layer on the second multilayer structure before depositing the second ferromagnetic layer.

### Claim 11 (depends on 1)

The method of claim 1, wherein a magnetization direction of the first multilayer structure is in the first direction and is determined by the magnetization direction of the top layer of the plurality of antiferromagnetic layers.

### Claim 12 (depends on 11)

The method of claim 11, wherein the magnetization direction of the top layer of the plurality of antiferromagnetic layers is formed using a laser or with a current pulse through the TMR element.

### Claim 13 (depends on 1)

The method of claim 1, wherein depositing the first multilayer structure comprises depositing sublayers, and
wherein each sublayer comprises a first heavy metal layer and a first ferromagnetic material layer.

### Claim 14 (depends on 13)

The method of claim 13, wherein depositing the second multilayer structure comprises depositing sublayers, and
wherein each sublayer comprises a second heavy metal layer and a second ferromagnetic material layer.

### Claim 15 (depends on 14)

The method of claim 14, wherein a total number of sublayers of the first multilayer structure is not equal to a total number of sublayers of the second multilayer structure.

### Claim 16 (depends on 14)

The method of claim 14, wherein a total number of sublayers of the first multilayer structure is equal to a total number of sublayers of the second multilayer structure.

### Claim 17 (depends on 14)

The method of claim 14, wherein the first heavy metal layer and/or the second heavy metal layer is a platinum layer, and the first ferromagnetic material layer and/or the second ferromagnetic material layer comprises a cobalt element.

### Claim 18 (depends on 1)

The method of claim 1, where depositing the antiferromagnetic material comprises depositing iridium manganese, platinum manganese or iron manganese.

### Claim 19

A tunnel magnetoresistance (TMR) element comprising:
antiferromagnetic material comprising a plurality of antiferromagnetic layers having magnetization directions alternating by layer between a first direction and a second direction opposite the first direction, a top layer of the plurality of antiferromagnetic layers having a magnetization direction in the first direction;
a ferromagnetic layer in direct contact with the top layer of the plurality of antiferromagnetic layers;
a first multilayer structure in direct contact with the ferromagnetic layer;
a metal layer in direct contact with the first multilayer structure; and
a second multilayer structure in direct contact with the metal layer, wherein the second multilayer structure is part of a reference layer,
wherein the ferromagnetic layer, the first multilayer structure and the second multilayer structure are each parallel to an x-y plane,
wherein the first direction is either in a z-direction or in a −z direction,
wherein a magnetization direction of the second multilayer structure is in the second direction and is determined by and is opposite of the magnetization direction of the top layer of the plurality of antiferromagnetic layer, and
wherein the magnetization direction of the second multilayer structure is a reference direction of the TMR element.

### Claim 20 (depends on 19)

The TMR element of claim 19, wherein the ferromagnetic layer is a first magnetic layer, and further comprising:
a second ferromagnetic layer on the second multilayer structure; and
an insulator layer in direct contact with the second ferromagnetic layer;
a free layer on the insulator layer.

### Claim 21 (depends on 20)

The TMR element of claim 20, wherein a magnetization direction of the free layer lies within the x-y plane.

### Claim 22 (depends on 20)

The TMR element of claim 20, further comprising a striped domain structure on the free layer.

### Claim 23 (depends on 22)

The TMR element of claim 22, wherein the striped domain structure comprises one or more sublayers.

### Claim 24 (depends on 23)

The TMR element of claim 23, wherein each sublayer comprises at least one heavy metal and at least one ferromagnetic material.

### Claim 25 (depends on 23)

The TMR element of claim 23, wherein each sublayer comprises at least one oxide layer and at least one ferromagnetic layer.

### Claim 26 (depends on 25)

The TMR element of claim 25, wherein each sublayer further comprises at least one heavy metal.

### Claim 27 (depends on 23)

The TMR element of claim 23, wherein each sublayer comprises a buffer layer.

### Claim 28 (depends on 20)

The TMR element of claim 20, wherein the metal layer is a first metal layer, and further comprising a second metal layer between the second ferromagnetic layer and the second multilayer structure.

### Claim 29 (depends on 19)

The TMR element of claim 19, wherein a magnetization direction of the first multilayer structure is in the first direction and is determined by the magnetization direction of the top layer of the plurality of antiferromagnetic layers.

### Claim 30 (depends on 19)

The TMR element of claim 19, wherein the first multilayer structure comprises sublayers, wherein each sublayer comprises a first heavy metal layer and a first ferromagnetic material layer.

### Claim 31 (depends on 30)

The TMR element of claim 30, wherein the second multilayer structure comprises sublayers, wherein each sublayer comprises a second heavy metal layer and a second ferromagnetic material layer.

### Claim 32 (depends on 31)

The TMR element of claim 31, wherein the first heavy metal layer and/or the second heavy metal layer is a platinum layer and the first ferromagnetic material layer and/or the second ferromagnetic material layer comprises a cobalt element.

### Claim 33 (depends on 31)

The TMR element of claim 31, wherein a total number of sublayers of the first multilayer structure is not equal to a total number of sublayers of the second multilayer structure.

### Claim 34 (depends on 31)

The TMR element of claim 31, wherein a total number of sublayers of the first multilayer structure is equal to a total number of sublayers of the second multilayer structure.

### Claim 35 (depends on 19)

The TMR element of claim 19, where the antiferromagnetic material comprises iridium manganese, platinum manganese or iron manganese.

### Claim 36

A magnetic field sensor comprising:
a bridge comprising:
a source;
a first leg comprising:
a first tunnel magnetoresistance (TMR) element; and
a second TMR element electrically in series with the first TMR element and electrically closer to the source than the first TMR element; and
a second leg comprising:
a third TMR element; and
a fourth TMR element electrically in series with the third TMR element and electrically closer to the source than the third TMR element,
wherein the first TMR element, the second TMR element, the third TMR element and the fourth TMR elements each comprises:
antiferromagnetic material comprising a plurality of antiferromagnetic layers having magnetization directions alternating by layer between a first direction and a second direction opposite the first direction, a top layer of the plurality of antiferromagnetic layers having a magnetization direction in the first direction;
a ferromagnetic layer in direct contact with the top layer of the plurality of antiferromagnetic layers;
a first multilayer structure in direct contact with the ferromagnetic layer;
a metal layer in direct contact with the first multilayer structure; and
a second multilayer structure in direct contact with the metal layer, wherein the second multilayer structure is part of a reference layer,
wherein the ferromagnetic layer, the first multilayer structure and the second multilayer structure are each parallel to an x-y plane,
wherein the first direction is either in a z-direction or in a −z direction,
wherein a magnetization direction of the second multilayer structure is in the second direction and is determined by and is opposite of the magnetization direction of the top layer of the plurality of antiferromagnetic layer,
wherein the magnetization direction of the second multilayer structure is a reference direction of the TMR element, and
wherein the first TMR element and the fourth TMR element each have a reference direction in the z-direction, and
wherein the second TMR element and the third TMR element each have a reference direction in the −z-direction.